Chemistry Deffinitions

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Hydrocarbon
A compound of hydrogen and carbon only.
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Homologous Series
A series of organic compounds having the same functional group but with each successive member differing by CH2
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Functional Group
A group of atoms responsible for the characteristics reactions of a compound.
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Saturated
Containing single bonds only.
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Unsaturated
Containing at least one carbon to carbon multiple bond.
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Empirical Formula
The simplest whole number ratio of atoms of each element present in a compound.
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Molecular Formula
The actual number of atoms of each element in a molecule.
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Structural Isomers
Compounds with the same molecular formula but with different arrangement of the atoms in space.
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Stereoisomerism
Compounds with the same structural formula but with a different arrangement of the atoms in space.
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E/Z Isomerism
An example of stereoisomerism, in terms of restricted rotation about a double bond and the requirement for two different groups to be attached to each carbon of the C=C group.
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Cis-Trans Isomerism
A special case of E/Z isomerism in which two of the substituent groups .
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Fractional Distillation
Separation of liquid mixture into fractions with different boiling points.
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Catalytic Cracking
The breaking down on long chained saturated hydrocarbons to form more useful alkanes (shorter chained) and alkenes.
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Biofuel
A fuel that is derived from recently living material such as plants or from the wast of animals.
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'Curly Arrow'
The movement of an electron pair, showing either the breaking or formation of a covalent bond.
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Homolytic Fission
The breaking of a covalent bond where the shared pair of electrons are split equally, forming two radicals.
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Heterolytic Fission
The breaking of a covalent bond where the shared pair of electrons are not split equally, forming a cation and an anion.
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Electrophile
Species attracted to an electron rich centre where is donates a pair of electrons to form a new covalent bond.
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Nucleophile
A species attracted to an electron deficient centre where is donates a pair of electrons to form a new covalent bond.
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Radical
A species with an unpaired electron.
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Exothermic
Heat is given out to the surroundings ( the reactants lose energy).
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Endothermic
Heat is taken in from the surroundings ( the reactants gain energy).
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Activation Energy
The minimum energy required to start a reaction by the breaking of bonds.
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Standard Conditions
A pressure of 100kPa (1 atmosphere), a stated temperature, usually 298K (25'C) and a concentration of 1.0mold^-3 (for reactions with aqueous solutions).
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(Standard) Enthalpy Change of Reactions
The enthalpy change that accompanies a reaction in the molar quantities expressed in a chemical equation (under standard conditions, all reactants and products being in their standard states).
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(Standard) Enthalpy Change of Formation
The enthalpy change that takes place when one mole of compound is formed from its constituent elements (under standard conditions, all reactants and products being in their standard states).
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(Standard) Enthalpy Change of Combustion
The enthalpy change that takes place when one mole of a substance reacts completely with oxygen (under standard conditions, all reactants and products being in their standard states).
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Average Bond Enthalpy
The average enthalpy change that takes place when breaking, by homolytic fission, 1 mole of a given type of bond in the molecules of a gaseous species.
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Catalyst
Speeds up a reaction without being consumed by the overall reaction.
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Volatility
The ease that a liquid turns into a gas (increases as boiling point decreases).
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Dynamic Equiliburm
The equilibrium that exists in a closed system when the rate of the forward reaction is equal to the rate of the reverse reaction.
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Le Chatelier's Principle
When a system in dynamic equilibrium is subjected to change, the position of equilibrium will shift to minimise the change.
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Atom Economy
Molecular mass desired product/Molecular mass sum of products X 100
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Atomic Number
The number of protons in the nucleus of an atom.
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Mass Number
The number of protons and neutrons in the nucleus of an atom.
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Relative Isotopic Mass
The mass of an atom of an isotope compared to 1/12 the mass of an atom C-12.
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Relative Atomic Mass
The weighted mean mass of an atom of an element compared with 1/12 the mass of an atom of C-12.
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Isotopes
Atoms of the same element with a different number of neutrons.
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Mole
The amount of substance containing as many particles as there are carbon atoms in exactly 12g of C-12.
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Avogadro's Constant
The number of particles per mole of a substance (6.02x10^23)
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Molar Mass
The mass in g per mole of a substance. Units are gmol^-1
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Water of Crystallisation
The water present in a compound giving the compound giving the compound a crystalline appearance.
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Acid
Release H+ ions in solution (proton donor)
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Base
A proton acceptor
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Alkali
A soluble base that release OH- ions when in solution.
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Salt
A compound produced when a H+ ion from an acid is replaced by a metal or another positive ion, such as the ammonium ion.
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Anhydrous
When all the waters of cyrstallisation have been removed from a compound.
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Hydrated
When water of crystallisation is present in a crystal compound.
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Oxidation Number
A measure of the number of electrons that an atom uses to bond with an atoms of a different element.
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Oxidation
The loss of electrons/an increase in oxidation number (State).
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Oxidising agent
A reagent which oxidises another species (gets reduced itself).
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Reduction
The gain of electrons/a decrease in oxidation number (state).
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Reducing Agent
A reagent which reduces another species (gets oxidised itself).
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Redox
A reaction where both oxidation and reduction take place.
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Displacement Reaction
A reaction in which a more reactive element displaces a less reactive element from an aqueous solution of its halide ions.
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Disproportionation Reaction
A reaction in which an element is simultaneously oxidised and reduced.
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Atomic Orbital
A region within an atom that can hold up to two electrons, with opposite spins,
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s/p/d Block Element
Highest energy sub-shell is a s/p/d sub shell.
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Ionic Bond
The electrostatic attraction between oppositely charged ions.
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Covalent Bond
The sharing of pair of electrons between two atoms.
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Dative (covalent) bond
The sharing of a pair of electrons between two atoms where only one of the atoms supplies both the electrons shared.
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Electronegativity
The ability of an atom to attract the bonding electrons towards itself in a covalent bond.
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Metallic Bonding
The attraction of positive metal ions to delocalised electrons.
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Periodicity
The repeating pattern of trends across different periods.
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Hydrogen Bond
A dipole-dipole attraction between a slightly positive hydrogen on one molecule and a lone pair of electrons on a highly electronegative atom (N, O, F) of another molecule.
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First ionisation energy
The energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions. Units are kJmole^-1
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Successive Ionisation Energy
A measure of the energy required to remove each electron in turn.
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Other cards in this set

Card 2

Front

A series of organic compounds having the same functional group but with each successive member differing by CH2

Back

Homologous Series

Card 3

Front

A group of atoms responsible for the characteristics reactions of a compound.

Back

Preview of the back of card 3

Card 4

Front

Containing single bonds only.

Back

Preview of the back of card 4

Card 5

Front

Containing at least one carbon to carbon multiple bond.

Back

Preview of the back of card 5
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